Continuous acetate production through microbial electrosynthesis from <scp>CO₂</scp> with microbial mixed culture

Abstract

Abstract BACKGROUND Microbial electrosynthesis represents a promising approach for renewable energy storage in which chemically stable compounds are produced using CO 2 as feedstock. This report describes the continuous production of acetate through microbial electrosynthesis from CO 2 and assesses how the production rates could be increased. RESULTS A continuous acetate production rate of 0.98 mmol C L NCC −1 d −1 was obtained using CO 2 as feedstock and with pH control around 5.8. These conditions increased substrate availability and favoured microbial electrosynthesis. Cyclic voltammograms demonstrated the electroautotrophic activity on the biocathode surface, which increased with pH control and caused current demand and acetate production rate to rise exponentially. CONCLUSION pH decrease was shown to be an effective strategy to increase substrate availability and enhance microbial electrosynthesis. By making microbial electrosynthesis a feasible technology, CO 2 could become an alternative feedstock for the carboxylate platform. © 2015 Society of Chemical Industry